Use of magnesium as a drug in chronic kidney disease

Abstract

From chronic kidney disease (CKD) Stage 4 onwards, phosphate binders are needed in many patients to prevent the development of hyperphosphataemia, which can result in disturbed bone and mineral metabolism, cardiovascular disease and secondary hyperparathyroidism. In this review, we re-examine the use of magnesium-containing phosphate binders for patients with CKD, particularly as their use circumvents problems such as calcium loading, aluminum toxicity and the high costs associated with other agents of this class. The use of magnesium hydroxide in the 1980s has been superseded by magnesium carbonate, as the hydroxide salt was associated with poor gastrointestinal tolerability, whereas studies with magnesium carbonate show much better gastrointestinal profiles. The use of combined magnesium- and calcium-based phosphate binder regimens allows a reduction in the calcium load, and magnesium and calcium regimen comparisons show that magnesium may be as effective a phosphate binder as calcium. A large well-designed trial has recently shown that a drug combining calcium acetate and magnesium carbonate was non-inferior in terms of lowering serum phosphate to sevelamer-HCl and had an equally good tolerability profile. Because of the high cost of sevelamer and lanthanum carbonate, the use of magnesium carbonate could be advantageous and drug acquisition cost savings would compensate for the cost of introducing routine magnesium monitoring, if this is thought to be necessary and not performed anyway. Moreover, given the potential cost savings, it may be time to re-investigate magnesium-containing phosphate binders for CKD patients with further well-designed clinical research using vascular end points.

Keywords: chronic kidney disease; cost-effectiveness; magnesium; phosphate binder.

Fig. 1.

Significant decrease in serum calcium concentration in patients given a phosphate binder consisting of calcium acetate plus magnesium carbonate (versus calcium carbonate alone) [14]. (Reprinted from Deuber [14], with permission from Dustri-Verlag, Dr. Karl Feistle GmbH & Co.).

Fig. 2.

Lower serum calcium levels in patients given a magnesium-containing phosphate binder (magnesium carbonate plus calcium carbonate) than in those taking calcium acetate alone (P = 0.003) Reprinted from Spiegel et al. [15], Copyright 2007, with permission from Elsevier.

Fig. 3.

Reductions in serum phosphate levels with treatment with either a magnesium-containing phosphate binder (calcium acetate plus magnesium carbonate) or sevelamer hydrochloride [20]. Reprinted from de Francisco et al. [20], by permission of Oxford University Press.

Fig. 4.

Total serum calcium levels in patients given a magnesium-containing phosphate binder (calcium acetate plus magnesium carbonate) or sevelamer hydrochloride [20]. Reprinted from de Francisco et al. [20], by permission of Oxford University Press.